PURIFICATION AND CHARACTERIZATION OF 4 BILIVERDIN-BINDING PROTEINS FROM LARVAL HEMOLYMPH OF THE COMMON CUTWORM, SPODOPTERA-LITURA

Four biliverdin-binding proteins (BPs) were purified from the laval ha emolymph of Spodoptera a litura by a combination of KBr gradient ultra centrifugation and chromatofocusing, In the order of highest isoelectr ic point, we named the proteins BP-1, BP-2, BP-3 and BP-4, All BPs wer e composed of subunits of 165 kDa and their native molecular weights w ere estimated as 390 kDa by gel filtration. In addition to biliverdin, they contained more than 3% lipids (cholesterol, cholesterol ester, t riacylglycerol, diacylglycerol, monoacylglycerol and phospholipid) and ca 3% carbohydrates (D-fucose, D-mannose, D-glucose, D-galactose and N-acetyl-D-glucosamine). The amino acid composition of BP-4 differed s lightly from the other BPs, In Ouchterlony's immunodiffusion tests, an tiserum against BP-2 showed cross-reactivities with BP-1, BP-2 and BP- 3, and antiserum against BP-4 only reacted with BP-4, An immunoblottin g test revealed strong reactivities between BP-2 antiserum and BP-1, B P-2 and BP-3, and weak cross-reactivity with BP-4, Antiserum,against B P-4 only showed strong reactivity with its own antigen, and weak cross -reactivities with BP-1, BP-2 and BP-3.